HTML Form to PM / Post?

This is about "Luky"s Tip and Trick guide on how to make a HTML Contact form found in here.

I've been trying to find out how to make this code

Code:

<form action="mailto:your_e-mail_address@domain.com" method="post" enctype="text/plain">

Into a code that it would send the form into a Private Message on the forums, or into a Post on forums.

I know it can't be impossible (since when was anything impossible) because you can make a contact form through admin panel to be sended as Private Message, but that is only one contact form and its automated by forumotion and I want to make many contact forms which would all be sent to PM or made into Post.

So any smart guy/gal out there who knows more of HTML than I do (lol this applies to everyone really), could have a check on it and tell what i need to edit on the code? Please

This is how the form looks now: (if anyone wants to look)
Link to my form
You can also PM me for some guide on how to make it like that if there are other newbeginners like myself

You would need PHP to do it, and forumotion does not support it